Device manufacturing apparatus and method of controlling same

ABSTRACT

An apparatus for processing an article in order to manufacture a device includes a process chamber in which the article is processed; a relay chamber; a first load-lock chamber disposed between an outside of the apparatus and the relay chamber; a second load-lock chamber disposed between the relay chamber and the process chamber; a first adjusting mechanism configured to adjust atmosphere in the process chamber to a first atmosphere; and a second adjusting mechanism configured to adjust atmosphere in the relay chamber to a second atmosphere that is an intermediate atmosphere between the first atmosphere and atmosphere of the outside.

FIELD OF THE INVENTION

This invention relates to a technique for manufacturing devices such as semiconductor elements. More particularly, the invention relates to an atmosphere adjusting technique for transferring an article between the interior and exterior of a device manufacturing apparatus.

BACKGROUND OF THE INVENTION

In a case where the interior and exterior environments of an apparatus differ greatly from each other, it is necessary to provide a relay-like process chamber such as a load-lock chamber for changing over the environment. For example, if there is a substance of some kind between an exposure source and an article to be exposed in a EUV exposure apparatus or a direct-writing exposure apparatus that writes directly using an electron beam or the like, this will have an effect upon the optical path of the exposing light or exposing beam and accurate exposure will no longer be possible. For this reason, it is necessary that the optical path of the exposing light or exposing beam and the space in which the wafer stage exists within the apparatus be held in a state of high vacuum. Further, if oxygen or moisture content is irradiated with an F₂ laser in an F₂ exposure apparatus, the laser beam is absorbed and the exposure energy attenuated. This makes it necessary to fill the optical path with high-concentration nitrogen gas. In a case where the interior and exterior environments of an apparatus thus differ greatly, it is necessary to change over the environment using a load-lock chamber.

An example of the structure of an ordinary apparatus using a load-lock chamber will be described with reference to FIG. 4.

In a case where the interior and exterior environments of the apparatus differ and an article to be processed is transported into the apparatus (or a processed article is extracted from the interior of the apparatus), a load-lock chamber is used in order to make the process environment such as pressure or gaseous component outside the apparatus conform to that of the process section inside the apparatus.

The apparatus illustrated in FIG. 4 has one such load-lock chamber 10. The load-lock chamber 10 has two gates, namely an outer gate 9 and an inner gate 11, capable of cutting off the interior of the apparatus from the outside. When a processed article is transferred from the interior of the apparatus, first the two gates 9 and 11 are closed and the environment in the load-lock chamber 10 is adjusted so as to be approximately the same as that in the apparatus interior 15 by a pressure regulating mechanism 13. The inner gate 11 is then opened, the processed article inside the apparatus is extracted and placed inside the load-lock chamber 10 and the inner gate 11 is closed again. After the environment inside the load-lock chamber 10 is made approximately the same as that outside the apparatus, the outer gate 9 is opened and the processed article Is transferred to the exterior of the apparatus. When an article is transported into the interior of the apparatus, it will suffice to reverse the above-described operation.

There are many cases where only a single load-lock chamber 10 is provided, as illustrated in FIG. 4. Even when only a single load-lock chamber 10 exists, no particular problems arise as in a case where the difference between the interior and exterior environments is small or a case where the difference is large but the application permits the processing time needed to adjust the environment.

However, in instances where the environment of the process section inside the apparatus is markedly different from the exterior environment in which the apparatus has been installed, there is a marked increase in process time necessary for the adjustment of environment within the load-lock chamber produced when the article such as a wafer is transported into the apparatus. This results is a decline in throughput. Such a case where there is a marked difference in environments is one where the pressure inside the apparatus is lower than that of a high vacuum (on the order of 10⁻⁵ pa), as in an EUV exposure apparatus, or one where the optical path of a laser is filled with high-purity nitrogen gas, as in an exposure apparatus that employs an F₂ laser.

With the aim of preventing such a decline in throughput, the specification of Japanese Patent Application Laid-Open No. 2000-150395 proposes an arrangement in which a plurality of load-lock chambers are provided between the external environment of an apparatus under atmospheric pressure and a vacuum process chamber, thereby allowing processing to be performed in parallel. If this arrangement is adopted, parallel operation in evacuation and exhaust processes can be performed. This makes it possible to shorten waiting time for the purpose of making the interior and exterior environments agree.

However, by just simply arranging load-lock chambers in parallel as in the method set forth in the specification of Japanese Patent Application Laid-Open No. 2000-150395, the pressure in each individual load-lock chamber is reduced from atmospheric pressure to the pressure of the process chamber every time. Consequently, if the set pressure in the vacuum process chamber is extremely low, as in the case of the pressure of ultra-high vacuum, it is difficult to make the pressure in each load-lock chamber reach the target pressure in a short time. For example, it is preferred that the process pressure in an apparatus such as an EUV exposure apparatus be less than ultra-high vacuum pressure (i.e., less than 10⁻⁵ pa). However, when the set pressure is such a low pressure, the time needed for chamber evacuation becomes extremely lengthy and a decline is throughput cannot be avoided even if a plurality of load-lock chambers are provided.

In order to shorten the time needed to attain vacuum, a method of simply strengthening exhaust capability or heating the load-lock chamber is conceivable. For example, if a load-lock chamber is baked to release the gas from within or a pump having a strong exhaust capability is used, an improvement in vacuum attainment time can be achieved. In this case, however, there is the possibility that a new problem will arise.

By way of example, it is effective to perform the baking of a load-lock chamber at as high a temperature as possible. However, there is the concern that the heat from baking will penetrate into the interior of the apparatus and affect exposure performance and that the wafer undergoing processing will be subjected to thermal damage, depending upon the set temperature. Further, it is not easy to select a material that can withstand repetitive shifts between room temperature and high temperature and between atmospheric pressure and ultra-high vacuum pressure over an extended period of time, and it is not easy to realize a vacuum-seal mechanism for forming such a load-lock chamber. In addition, if a pump having a strong exhaust capability is used, vacuum attainment time can be shortened because the exhaust speed rises. However, merely adopting a pump having an excellent exhaust performance causes dust to rise within the process chamber and can cause the wafer to be contaminated.

SUMMARY OF THE INVENTION

The present invention has been devised in view of the background set forth above and an exemplary object thereof is to provide a novel technique relating to transfer of an article between the interior and exterior of a device manufacturing apparatus.

According to one aspect of the present invention, there is provided an apparatus for processing an article in order to manufacture a device, the apparatus comprising: a process chamber in which the article is processed; a relay chamber; a first load-lock chamber disposed between an outside of the apparatus and the relay chamber; a second load-lock chamber disposed between the relay chamber and the process chamber; a first adjusting mechanism configured to adjust atmosphere in the process chamber to a first atmosphere; and a second adjusting mechanism configured to adjust atmosphere in the relay chamber to a second atmosphere that is an intermediate atmosphere between the first atmosphere and atmosphere of the outside.

Also, according to another aspect of the present invention, there is provided a method applied to an apparatus for processing an article in order to manufacture a device, the article being transferred from an outside of the apparatus into a process chamber where the article is processed, the method comprising steps of: adjusting atmosphere in the process chamber to a first atmosphere; adjusting atmosphere in a relay chamber, which is disposed between the process chamber and the outside, to a second atmosphere that is an intermediate atmosphere between the first atmosphere and atmosphere of the outside; transferring the article from the outside into the relay chamber via a first load-lock chamber; and transferring the article from the relay chamber into the process chamber via a second load-lock chamber.

Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a diagram illustrating an example of equipment according to a first embodiment of the present invention;

FIG. 2 is a diagram illustrating an example of equipment according to a second embodiment of the present invention;

FIG. 3 is a diagram illustrating an example of equipment according to a third embodiment of the present invention;

FIG. 4 is a diagram illustrating an example of equipment constituting a vacuum exposure apparatus according to the prior art;

FIG. 5 is a flowchart useful in describing an operation for transferring a wafer by a controller; and

FIG. 6 is a flowchart useful in describing an operation for transferring a wafer by a controller.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described in detail in accordance with the accompanying drawings.

<Overview of the embodiments>

First, reference will be had to FIG. 1 to describe embodiments in a case where the present invention is applied to an exposure apparatus.

In the embodiments, an environment adjusting mechanism is provided between a process section (process chamber 15), which is located in an exposure apparatus, and the environment in which the apparatus is installed. The environment adjusting mechanism has a plurality of load-lock chambers 2 a, 2 b, 10 arranged in parallel and in series, and a transfer mechanism 6 constituted by a transfer robot or the like for transferring an article such as a wafer. The environment adjusting mechanism further includes regulating mechanisms 5 a, 5 b, 8, 13, 14 that are capable of individually controlling the environment in all of the sealable spaces from the exterior to the interior of the apparatus. The regulating mechanisms 5 a, 5 b, 8, 13, 14 use pressure regulating valves and vacuum pumps to make possible individual control of regulated pressure in each chamber (relay chamber 7 and process chamber 15) and in each load-lock chamber. The load-lock chambers 2 a, 2 b arranged in parallel are provided for the purpose of performing parallel processing in order to shorten the time needed for adjusting environment. On the other hand, the load-lock chamber 10 is disposed in series with the load-lock chambers 2 a, 2 b. The load-lock chamber 10 does not perform an adjustment of environment from the installation environment outside the apparatus to the wafer process environment (the environment inside the process chamber 15) in one stroke as is done conventionally. Rather, the load-lock chamber 10 is provided for the purpose of reducing waiting time for environmental adjustment via the relay chamber 7, which is in an intermediate state. Adopting such an arrangement improves the throughput of the apparatus.

The control method and appropriate pressure values will now be described in detail.

Condensation will be discussed first. There are instances where an article such as a wafer develops condensation owing to removal of heat by sudden adiabatic expansion. The humidity and pressure of the environment in which the article has been placed can be mentioned as conditions that give rise to condensation. It is known that if pressure is less than 100 pa in a case where the initial humidity is on the order of 50%, condensation will not occur even if the chamber is evacuated at high speed.

The raising of dust is another factor. An appropriate pressure value for preventing the attachment of dust differs depending upon the estimated size of the dust particles. That is, pressure at which the falling of dust under the force of gravity and the floating of dust due to Brownian movement are substantially in competition differs depending upon the size of the dust particles. Specifically, it is known that this pressure is 10⁻² pa in case of dust particles of size 10 nm, 10 pa in case of dust particles of size 50 nm, and 100 pa in case of a dust particles of size 0.1 μm. Further, when dust becomes electrically charged, it attaches itself to the wafer owing to the force of static electricity. This makes it necessary to perform de-electrification by a vacuum ionizer. Dust having a size of less than 50 nm usually is the object of de-electrification, although this will depend upon the specifications of the de-electrification apparatus.

In view of the foregoing, in this embodiment the entry load-lock chambers 2 a, 2 b for accepting an article such as a wafer are evacuated slowly from atmospheric pressure down to about 100 pa, then evacuation is performed at high speed on the side of pressure below this level. With regard to the relay chamber 7 for transferring the wafer from the entry load-lock chambers 2 a, 2 b to the load-lock chamber 10 of the process section (herein after referred to as the process-section load-lock chamber 10), it is preferred that the pressure here be made less than 10 pa in consideration of the fact that dust particles that have been de-electrified by a vacuum ionizer (not shown) are the object of interest. The pressure in the interior of the relay chamber 7 should at least be less than 100 pa, which is a pressure at which high-speed evacuation is possible. Further, with regard to the pressure of the process-section load-lock chamber 10 through which the article is introduced into the interior of the apparatus, the pressure varies from a pressure identical with that inside the relay chamber 7 to the pressure of the process section inside the apparatus (namely the pressure inside the process chamber 15).

The embodiments thus provide a space in which the environment is adjusted in multiple stages and a plurality of load-lock chambers for accepting an article between stages. This arrangement makes it possible for the adjustment of environment in each load-lock chamber to be completed in a short period of time.

It should be noted that when an environment filled to a high concentration with a specific gas such as nitrogen gas is prepared, an environment adjusting mechanism constituted by an environment adjusting space of a plurality of stages and a plurality of load-lock chambers connected thereto is effective for reasons similar to those for regulating the pressure environment. More specifically, a gas exchange can be performed at high speed by injecting nitrogen gas into the article entry load-lock chambers 2 a, 2 b after evacuation without raising dust particles in a manner similar to that of a vacuum apparatus. Further, by providing the relay chamber 7 having the intermediate environment from the article entry point to the process section inside the apparatus, the environment such as the nitrogen gas concentration or amount of water content can be made to approximate the state of the process section in stages in a manner similar to that of the pressure adjustment. Various embodiments will be described next.

<First Embodiment>

FIG. 1 illustrates the structure of a vacuum exposure apparatus for performing exposure treatment in an ultra-high vacuum, examples of the apparatus being an EUV exposure apparatus and a direct-writing exposure apparatus that uses an electron beam. Further, the vacuum exposure apparatus of FIG. 1 assumes a mass-production apparatus in which a multiplicity of wafers are processed.

As illustrated in FIG. 1, two entry load-lock chambers 2 a, 2 b are provided in order to carry in articles such as a wafer from outside the apparatus. This makes it possible to process the wafers in. parallel. The entry load-lock chamber 2 a (2 b) is provided with an outer gate 1 a (1 b) and an inner gate 3 a (3 b). The interior of the load-lock chamber can be made a sealed space by closing both gates. If the outer gate 1 a (1 b) is opened, the load-lock chamber is communicated with the exterior of the apparatus, and if the inner gate 3 a (3 b) is opened, the load-lock chamber is communicated with the relay chamber 7.

Further, the process-section load-lock chamber 10 is provided in order to carry the wafer into the interior of the apparatus (into process chamber 15). The process-section load-lock chamber 10 also is provided with an outer gate 9 and an inner gate 11. The interior of this load-lock chamber can be made a sealed space by closing both gates. If the outer gate 9 is opened, the load-lock chamber is communicated with the relay chamber 7, and if the inner gate 11 is opened, the load-lock chamber is communicated with the process chamber 15.

A transfer mechanism 6 transfers the article such as a wafer from the entry load-lock chamber 2 a or entry load-lock chamber 2 b to the process-section load-lock chamber 10 and includes a transfer robot or the like. The relay chamber 7 encloses the transfer mechanism 6 and is regulated so as to have a pressure between atmospheric pressure outside the apparatus and the pressure inside the process chamber 15. Further, pressure regulating mechanisms 5 a, 5 b, 8, 13 and 14 are capable of individually regulating the pressures within the entry load-lock chambers 2 a, 2 b, relay chamber 7, process-section load-lock chamber 10 and process chamber 15, respectively. A controller 101 controls the opening and closing of the gates of the load-lock chambers, the pressure regulating mechanisms and the transfer mechanism, etc.

Reference will now be had to the flowcharts of FIGS. 5 and 6 and to FIG. 1 to describe control of transfer of articles (wafers) in the exposure apparatus of this embodiment constructed as set forth above. FIGS. 5 and 6 are flowcharts useful in describing operation performed by the controller 101.

As mentioned above, it is assumed that the interior of the apparatus has been de-electrified by a vacuum ionizer, which is not shown. Further, in order to simplify the description, a case where a wafer is introduced from the entry load-lock chamber 2 a will be described. Operation is similar also in a case where a wafer is introduced from the entry load-lock chamber 2 b.

The entry load-lock chamber 2 a is regulated in such a manner that its pressure will become substantially identical with the pressure outside the apparatus. The outer gate 1 a thereof is then opened. That is, with the outer gate 1 a and inner gate 3 a in the closed state, the pressure inside the entry load-lock chamber 2 a is equalized with the pressure outside and the outer gate 1 a is then opened (steps S101, S102, S103).

A plurality of wafers introduced to a wafer carrier 4 a in advance are carried into the entry load-lock chamber 2 a. At this time the outer gate 1 a of the entry load-lock chamber 2 a has already been opened by the controller 101 and the inner gate 3 a has already been closed by the controller, as set forth above. The placement of the wafer carrier 4 a in the entry load-lock chamber 2 a may be performed manually or automatically by a transfer robot or the like. If completion of placement of the wafer carrier 4 a is detected, the controller 101 closes the outer gate 1 a (steps S104, S105) and the entry load-lock chamber 2 a starts to be depressurized by the corresponding pressure regulating mechanism 5 a (step S106). At this time the pressure in the load-lock chamber 2 a is lowered gradually from atmospheric pressure to 100 pa, and depressurization is then performed at high speed once the pressure has fallen below 100 pa, as mentioned above. By exercising such control of depressurization, it is possible to prevent the wafer from developing condensation due to adiabatic expansion caused by sudden evacuation, and to prevent the wafer from being contaminated by rising dust ascribable to an air stream produced within the entry load-lock chamber 2 a.

Depressurization is performed until the pressure becomes substantially equal to the pressure inside the relay chamber 7. After such depressurization the controller 101 opens the inner gate 3 a of the entry load-lock chamber 2 a (steps S107, S108). It is preferred that the pressure in the relay chamber 7 be on the order of 10 pa, as mentioned above. This is followed by transferring wafers in the wafer carrier 4 a to the process-section load-lock chamber 10 by the transfer mechanism 6 such as a vacuum robot (step S110). It should be noted that since the processing of steps S101 to S108 transfers a plurality of wafers as a unit to the entry load-lock chamber 2 a by means of the wafer carrier 4 a, the processing need be executed only one time for these plurality of wafers.

On the other hand, with regard to the process-section load-lock chamber 10, the pressure within this chamber is made the same as that (less than 10 pa) in the relay chamber 7 by the corresponding pressure regulating mechanism 13 with the outer gate 9 and inner gate 11 being in the closed state, after which the outer gate 9 is opened (steps S121, S122, S123). That is, it is assumed that at least at the time of execution of step S110, the process-section load-lock chamber 10 will have been regulated to a prescribed pressure by the pressure regulating mechanism 13 and that the outer gate 9 of on the side of the transfer mechanism 6 will have been opened. When it is detected that the wafers have been placed inside the process-section load-lock chamber 10 by the transfer mechanism 6 (“YES” at step S124), the controller 101 closes the outer gate 9 (step S125). The interior of the process-section load-lock chamber 10 is depressurized until its pressure becomes equal to that of the process chamber 15 [ultra-high vacuum pressure (i.e., less than 10⁻⁵ pa)] (steps S126, S127). The inner gate 11 is then opened (step S128). Under these conditions the wafers are transferred to the process chamber 15 by a transfer mechanism (not shown) within the process chamber 15 (step S130).

Although it is preferred that the pressure inside the process chamber 15 in the main body of the exposure apparatus be less than ultra-high vacuum pressure (less than 10⁻⁵ pa), it is conceivable, depending upon the structure and volume of the process section within the apparatus, that a further load-lock chamber capable of local evacuation will be added. (Adopting a high vacuum within the entirety of the apparatus is difficult if the apparatus is large in size. Accordingly, the area that is to be evacuated is reduced by providing a new load-lock chamber in the process section within the apparatus and locally evacuating the portion through which the light beam passes.) However, there are also cases where the above-mentioned set pressure value is decided comprehensively taking into account exposure process time, evacuation time and number of wafer accepting ports. For example, although the pressure in the relay chamber 7 for wafer transfer is desirably 10 pa, there are cases where this pressure will be 100 pa depending upon apparatus conditions.

As mentioned above, two entry load-lock chambers 2 a, 2 b are meant to allow evacuation to be performed in parallel. The number of these load-lock chambers is not limited to two and may be three or more. Further, it is also possible to construct an apparatus having a single entry load-lock chamber.

Operation for carrying wafers into the process chamber 15 from outside the apparatus has been described. Operation for transporting wafers from the process chamber 15 to the exterior of the apparatus is the reverse of the above-described operation. An example of this process will be described with reference to FIG. 6.

First, with the inner gate 11 and outer gate 9 of process-section load-lock chamber 10 closed, the pressure within the process-section load-lock chamber 10 is made equal to that inside the process chamber 15, after which the inner gate 11 is opened (steps S201 to S203). Then, after wafers are placed inside the process-section load-lock chamber 10 by a transfer mechanism (not shown), the inner gate 11 is closed (steps S204, S205). This is followed by elevating the pressure in process-section load-lock chamber 10 until it becomes equal to the pressure in the relay chamber 7. The outer gate 9 is opened after the pressures are equalized (steps S206 to S208). The transfer mechanism 6 is then driven to extract the wafers from the load-lock chamber 10 and place them in the relay chamber 7 (step S210).

It should be noted that it is not necessarily required to close the inner gate 11 of the process-section load-lock chamber 10 after the wafers have been carried into the process chamber 15 from the process-section load-lock chamber 10. Accordingly, if the inner gate 11 is open, naturally the operation at steps S201 to S203 in FIG. 6 is omitted.

On the other hand, the controller 101 closes the inner gate 3 a and outer gate 1 a of the entry load-lock chamber 2 a and regulates the pressure inside this load-lock chamber until it becomes equal to the pressure inside the relay chamber 7, after which the controller 101 closes the inner gate 3 a (steps S211 to S213). Under these conditions, the transfer mechanism 6 transfers the wafers, which have been extracted from the process-section load-lock chamber 10, to the interior of the entry load-lock chamber 2 a and places the wafers on the wafer carrier 4 a.

It should be noted that it is not necessarily required to close the inner gate 3 a of the entry load-lock chamber 2 a after the wafers have been carried into the relay chamber 7 from the entry load-lock chamber 2 a. Accordingly, if the inner gate 3 a is open, naturally the operation at steps S211 to S213 in FIG. 6 is omitted.

If completion of transfer into the entry load-lock chamber 2 a is detected, the controller 101 closes the inner gate 3 a, causes the pressure in this chamber to rise until it becomes equal to atmospheric pressure outside the apparatus and thenceforth opens the outer gate 1 a (steps S214 to S218). This is followed by transferring the wafers from the entry load-lock chamber 2 a by a transfer mechanism (not shown) or manually (step S220). The wafers can be extracted to the exterior of the apparatus by the above-described processing. It should be noted that since the entry load-lock chamber 2 a enables a plurality of wafers to be brought in and taken out in one batch by the wafer carrier 4 a, the processing of steps S215 to S218 need only be executed one time per plurality of wafers.

The advantages obtained by using the environment adjusting mechanism set forth above will now be described. Considered first will be a case where there is no serially arranged relay chamber 7 of the kind according to this embodiment, namely a case where only a single load-lock chamber intervenes, as in the example of the prior art shown in FIG. 4.

In order to shorten even slightly the time needed to attain a desired vacuum pressure, the smaller the volume and surface area of the object to be evacuated, the better. In particular, in the case of low pressure such as ultra-high vacuum pressure, surface area is important. Accordingly, if a comparison is made based upon length of evacuation time per cycle, it will be found that a method of supplying wafers one at a time is better than supplying wafers using the wafer carrier 4 a in terms of enabling a reduction in the volume of the load-lock chamber and the surface area thereof. This means that a short evacuation time per cycle will suffice. This is the reason why the process-section load-lock chamber 10 of this embodiment has a structure that supplies wafers one at a time. However, even though the method of supplying wafers one at a time is the same as the conventional method, this embodiment is such that evacuation is performed by lowering the pressure in the relay chamber 7, which is a pressure sufficiently lower than atmospheric pressure. Consequently, the total amount of air exhausted is much less in comparison with the conventional method (where evacuation starts from atmospheric pressure) and, as a result, the time needed to attain the target pressure can be shortened.

Further, in order to shorten target-pressure attainment time per wafer, it is better to place a plurality of wafers in vacuum simultaneously using the wafer carrier 4 a than to supply wafers one at a time. This is because the number of times the outer gate 1 a of the entry load-lock chamber 2 a is opened and closed can be reduced and because transfer time is curtailed. In this case, however, a great deal of time is required to attain the necessary degree of vacuum because of the large volume and surface area involved. This is extremely influential particularly in a case where the target pressure is low, as when the target pressure is ultra-high vacuum pressure. In this embodiment, however, the entry load-lock chambers 2 a, 2 b are evacuated only down to the pressure in the relay chamber 7, and not down to the region of ultra-high vacuum, from atmospheric pressure. This makes it possible to shorten process time. That is, the advantage of placing a plurality of wafers in vacuum simultaneously by the wafer carrier 4 a can be exploited.

Thus, in accordance with the first embodiment, as set forth above, the relay chamber 7 that has been set to a pressure (on the order of 10 pa) sufficiently lower than atmospheric pressure is provided between the entry load-lock chamber 2 a and the process-section load-lock chamber 10. As a result, the total amount of air exhausted from the process-section load-lock chamber 10 can be reduced in comparison with a case where vacuum is produced starting from atmospheric pressure. Furthermore, since volume and surface area can be reduced by introducing wafers from the relay chamber 7 to the process-section load-lock chamber 10 one at a time, processing is speeded up in the process-section load-lock chamber 10 where evacuation to ultra-high vacuum pressure is required. Further, since the wafer carrier 4 a is used to carry wafers into the entry load-lock chambers 2 a, 2 b that do not need to be evacuated to the region of ultra-high vacuum, amount of air exhausted per wafer can be reduced. Furthermore, by providing a plurality of entry ports and performing processing in parallel, the time needed to evacuate the entry load-lock chambers 2 a, 2 b can be reduced as well.

In accordance with the arrangement of this embodiment, therefore, processing time needed to adjust the environment can be shortened in comparison with the prior-art methods. The embodiment is particularly effective in cases where a plurality of wafers are processed simultaneously.

<Second Embodiment>

FIG. 2 is a diagram illustrating an example of equipment according to a second embodiment of the present invention. The arrangement using the wafer carrier 4 a as described in the first embodiment is very effective in cases where a number of wafers are processed simultaneously. In a case where the number of wafers processed is small, however, there is the concern that process time will be lengthened rather than shortened owing to the large volume of air that must be exhausted in the entry load-lock chamber 2 a.

In the second embodiment, an entry load-lock chamber 2 c that is capable of introducing wafers one at a time is provided taking the above-mentioned case into consideration. Adopting such an arrangement makes it possible to offset the drawback of increased amount of air exhaust mentioned above.

Depending upon the method of apparatus operation, arrangements in which there is a mixture of wafer-carrier entry ports or in which a plurality of wafer-by-wafer entry ports are provided are also conceivable. Further, although only one entry port for wafers one at a time is provided in FIG. 2, two or more may be provided.

Thus, the second embodiment provides the load-lock chamber 2 c, which makes it possible to mount wafers one at a time, besides using a wafer carrier to supply wafers. This is one exemplary variation of a method of supplying wafers. This arrangement is effective in a case where small lots of wafers are processed.

<Third Embodiment>

An example of the structure of a vacuum apparatus has been described in the first and second embodiments. The environment adjusted in this vacuum apparatus is pressure. However, the arrangements of the first and second embodiments are effective also in a case where a gaseous composition or water content, etc., is adjusted. FIG. 3 is a diagram illustrating an example of equipment according to a third embodiment of the present invention. The third embodiment provides a gas control mechanism in addition to a pressure control mechanism, thereby similarly raising throughput even in an environment other than a vacuum environment.

In the third embodiment, gas regulating mechanisms 16 to 20 are provided in addition to pressure regulating mechanisms similar to those of the first embodiment. The gas regulating mechanisms 16 to 20 each comprise a mechanism (e.g., a mass-flow controller) for injecting a high-purity specific gas such as nitrogen gas, and a drier for removing water content. These control each chamber and load-lock chamber individually. The gas regulating mechanisms 16 to 20 are installed for the purpose of regulating the respectively connected sealable spaces to desired gas components.

Even in a case where the purity of the gas component required for the interior of the process chamber 15 is extremely stringent, adjustment time can be shortened more by relying upon the intermediary of the relay chamber 7, as described in the pressure adjustment of the first and second embodiments, than by performing adjustment at one stroke from the installation environment external to the apparatus. That is, for reasons similar to those for adjusting the pressure environment, an environment adjusting mechanism composed of a plurality of load-lock chambers is useful also when preparing an environment for filling a space with a specific gas such as nitrogen gas at a high concentration.

In accordance with each of the foregoing embodiments as described above, providing a plurality of ports for acceptance of wafers from atmospheric pressure makes it possible to execute depressurization of the entry load-lock chambers, which are provided at the acceptance ports, simultaneously and in parallel. As a result, effective depressurization time can be shortened and an improvement in throughput achieved.

In a case where the environment that supplies an article such as a wafer differs greatly from the process environment inside the exposure apparatus, process time needed for the environmental adjustment can be reduced and throughput raised by providing an environment adjusting mechanism comprising a plurality of load-lock chambers and passing wafers through an intermediate environment.

Further, when a wafer under atmospheric pressure is fed into the process section within an apparatus having a vacuum space or nitrogen-gas purging space, it is necessary to carry out evacuation or gas exchange. In a case where the required process environment is very stringent, the time needed for the adjustment of environment is prolonged, waiting time up to exposure process lengthens and throughput declines.

By contrast, with the first embodiment, processing at a speed higher than that with the conventional method becomes possible by providing a plurality of entry load-lock chambers in parallel, placing the entry load-lock chambers in series with a load-lock chamber of a process section, as illustrated in FIG. 1, and establishing an appropriate environment in each of the chambers. Further, depressurization of a plurality of wafers is performed at one time using a wafer carrier or the like and relying upon the intermediary of a plurality of entry load-lock chambers, and the wafers are carried into interior of the apparatus one at a time. The result is greatly improved throughput.

Further, in relation to the entry load-lock chambers, it is so arranged that a plurality of wafers can be carried in and out at one time using a wafer carrier. This means that the number of times a gate valve of the load-lock chamber is opened and closed can be reduced. That is, the amount of air actually exhausted can be reduced more by introducing a plurality of wafers into a load-lock chamber at one time than by accepting the wafers one at a time. This makes it possible to achieve improved throughput.

As illustrated in each of the foregoing embodiments, exercising control in such a manner that the plurality of load-lock chambers will attain prescribed pressures makes it possible to perform high-speed processing while suppressing the effects of wafer contamination, which is due to rising dust, and wafer condensation. That is, in an entry load-lock chamber for accepting a wafer, there is a changeover between high-speed evacuation and low-speed evacuation about a boundary value of 100 pa. Further, by making the value of pressure less than 100 pa in the transfer area of the relay chamber 7 and in the process-section load-lock chamber 10 for introducing a wafer to the apparatus process area (the process chamber 15) and, in particular, by making the pressure 10 pa in the relay chamber 7, throughput can be improved while contamination due to dust is suppressed.

With regard to the above-described advantages of the vacuum apparatus, namely a reduction in the total amount of air exhausted and the prevention of rising dust, it is obvious that the invention is similarly effective also with regard to an apparatus that requires filling with a specific gas such as nitrogen gas at a high concentration. Accordingly, when a gas exchange is performed in a case where an apparatus is filled with a specific gas such as nitrogen gas at a high concentration, it is preferred that the speed at which the load-lock chambers are evacuated or at which they are filled with gas be controlled appropriately in accordance with the pressure inside the load-lock chambers. Further, although each of the embodiments indicates an arrangement in which a plurality of entry load-lock chambers and a single process-section load-lock chamber 10 are provided, a plurality of the process-section load-lock chambers 10 may be provided.

Thus, in accordance with the implementation of the present invention as described above, the introduction and extraction of an article to and from an apparatus can be performed at high speed and the throughput of the apparatus can be raised in a case where the environment inside the apparatus differs greatly from the environment outside the apparatus.

As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.

This application claims the benefit of Japanese Patent Application No. 2005-080595, filed on Mar. 18, 2005, which is hereby incorporated by reference herein in its entirety. 

1. An apparatus for processing an article in order to manufacture a device, said apparatus comprising: a process chamber in which the article is processed; a relay chamber; a first load-lock chamber disposed between an outside of said apparatus and said relay chamber; a second load-lock chamber disposed between said relay chamber and said process chamber; a first adjusting mechanism configured to adjust atmosphere in said process chamber to a first atmosphere; and a second adjusting mechanism configured to adjust atmosphere in said relay chamber to a second atmosphere that is an intermediate atmosphere between the first atmosphere and atmosphere of the outside.
 2. An apparatus according to claim 1, wherein said first adjusting mechanism is configured to adjust atmosphere in said process chamber to a first degree of vacuum as the first atmosphere, and said second adjusting mechanism is configured to adjust atmosphere in said relay chamber to a second degree of vacuum, which is an intermediate vacuum between the first degree of vacuum and a degree of vacuum at the outside, as the second atmosphere.
 3. An apparatus according to claim 1, wherein said first adjusting mechanism is configured to adjust atmosphere in said process chamber to an atmosphere of inert gas at a first density as the first atmosphere, and said second adjusting mechanism is configured to adjust atmosphere in said relay chamber to an atmosphere of the inert gas at a second density, that is an intermediate density between the first density and density of the inert gas at the outside, as the second atmosphere.
 4. An apparatus according to claim 1, wherein said first and second load-lock chambers are configured so that capacity of said first load-lock chamber for accommodating the article is greater than that of said second load-lock chamber.
 5. An apparatus according to claim 1, wherein said apparatus includes a plurality of said first load-lock chambers.
 6. An apparatus according to claim 1, wherein said apparatus includes a plurality of said second load-lock chambers.
 7. An apparatus according to claim 1, wherein said apparatus includes a plurality of said first load-lock chambers having different capacities for accommodating the article.
 8. An apparatus according to claim 1, further comprising an exhaust mechanism configured to exhaust gas from said first load-lock chamber, wherein said exhaust mechanism is configured to change over exhaust rate based on degree of vacuum in said first load-lock chamber.
 9. An apparatus according to claim 1, further comprising a supply mechanism configured to supply inert gas into said first load-lock chamber, wherein said supply mechanism is configured to change over supply rate of the inert gas based on pressure in said first load-lock chamber.
 10. A method applied to an apparatus for processing an article in order to manufacture a device, the article being transferred from an outside of the apparatus into a process chamber where the article is processed, said method comprising steps of: adjusting atmosphere in the process chamber to a first atmosphere; adjusting atmosphere in a relay chamber, which is disposed between the process chamber and the outside, to a second atmosphere that is an intermediate atmosphere between the first atmosphere and atmosphere of the outside; transferring the article from the outside into the relay chamber via a first load-lock chamber; and transferring the article from the relay chamber into the process chamber via a second load-lock chamber. 